CN1810367A - Dehydrogenating catalyst for preparing styrene - Google Patents

Abstract

The present invention relates to one kind of dehydrogenating catalyst for preparing styrene and aims at raising the activity and selectivity of low potassium catalyst. The technological scheme of the present invention includes adding proper amount of Nb oxide to and controlling potassium oxide content below 11 wt% in the Fe-K-Ce-Mo-Mg-Ca catalyst system. The catalyst system may be used widely in the industrial production of dehydrogenating to produce styrene.

Description

Be used to prepare cinnamic dehydrogenation

Technical field

The present invention relates to a kind of cinnamic dehydrogenation that is used to prepare.

Background technology

Industrial styrene mainly is to be made by ethylbenzene catalytic dehydrogenation, and catalyst system therefor is to be that main active component, potassium oxide are the Fe-series catalyst of main co-catalyst with the iron oxide.As everyone knows, potassium can become order of magnitude ground to increase the activity of iron oxide, and can promote water gas reaction that carbon deposit is eliminated, and makes the catalyst automatic regeneration, therefore, from first generation Fe-series catalyst, all contains potassium in the composition.

" energy crisis " of early 1980s sharply raises up the steam expense in the production of styrene process, and the energy-saving catalyst of high potassium arises at the historic moment.The potassium content height helps to improve the anti-carbon deposit and the anti-reducing power of catalyst in the catalyst, can obviously reduce water and ethylbenzene feed ratio in the dehydrogenating technology process, and certain energy-saving effect is arranged.But because all there are thermograde in reactor bed and catalyst particles intragranular, potassium can move: in reactor bed, potassium is moved to the lower outlet position of temperature by the higher reactor inlet of temperature with reaction mass; In catalyst granules inside, because the strong heat absorptivity effect of dehydrogenation reaction makes core temperature of particle a little less than the periphery, so, because of making potassium, the JND of potassium oxide vapour pressure exists tendency to the migration of particle center.After catalyst operation a period of time, potassium is obviously higher in the concentration at particle center, the outside because potassium deficiency of particle and loss of catalytic activity progressively, and the particle center is but because potassium content is too high and active on the low side, and this is the major reason that causes catalysqt deactivation.As laid-open U.S. Patents 4758543,5190906, the main composition of catalyst is the high Fe-K-Ce-Mo of potassium content, and such catalyst demonstrates high activity at initial operating stage, but catalyst life is short.The hygroscopicity of high in addition potassium catalyst is strong, water resistance is poor, easily causes catalyst efflorescence, caking, and the beds pressure drop is increased.

Many weakness that high potassium catalyst exposes in use impel people to reduce potassium content in the catalyst by every means.But along with the minimizing of potassium content in the catalyst, activity of such catalysts and selectivity all have decline to a certain degree, and especially selectivity descends more obvious.Therefore, in the potassium content, seek to overcome the weakness of low potassium catalyst in reducing catalyst, improve low potassium catalyst selectivity and active method is the target that the researcher makes great efforts always.

Summary of the invention

Technical problem to be solved by this invention is to exist low potassium catalyst activity not high in the conventional art, and especially the low problem of selectivity provides a kind of cinnamic dehydrogenation that is used to prepare.This catalyst has under the lower condition of potassium content, can keep the higher selectivity and the characteristics of catalytic activity.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind ofly be used to prepare cinnamic dehydrogenation, comprise following component by weight percentage:

(a) 60～88% Fe ₂O ₃

(b) 6～11% K ₂O;

(c) 4～11% CeO ₂

(d) 0.5～5% MoO ₃

(e) 0.5～5% MgO;

(f) 0.05～5% CaO;

(g) 0.05～5% Nb ₂O ₅

(h) 0.001～8% at least a oxide that is selected from Cu, Al, B, Zn, Mn, W, Ni, Sn, Pb, Bi, Ge.

In the above technical scheme by weight percentage, Nb ₂O ₅The consumption preferable range be 0.2～2%.

Used Fe is with Fe among the present invention ₂O ₃Form adds, Fe ₂O ₃Can be formed by iron oxide red and iron oxide yellow; Used K adds with sylvite or hydroxide form; Used Ce adds with oxide, hydroxide or cerium salt form; Used Mo adds with its salt or oxide form; Used Mg adds with oxide form; Used Ca adds with oxide, hydroxide or calcium salt forms; Used Nb adds with oxide form, and remaining element adds with its salt or oxide form.In preparation process of the present invention, except that the catalyst body composition, also should add binding agent and perforating agent, used binding agent can be selected from kaolin, diatomite or cement, and its addition is 1～8% of a total catalyst weight; Perforating agent can be selected from graphite, polystyrene microsphere, carboxymethyl cellulose, and its addition is 2～6% of a total catalyst weight.

Method for preparing catalyst of the present invention is as follows:

After metal oxide, adhesive, the perforating agent that will add by Fe, K, Ce, Mo, Mg, Ca, Nb, the selectivity of proportioning weighing mixes, add an amount of deionized water, make the face dough of toughness, suitable extrusion, becoming diameter through extrusion, pelletizing is 3 millimeters, long 8～10 millimeters particle, in 80～120 ℃ of dryings 4 hours, 500～1000 ℃ of following roastings 4 hours, just can obtain finished catalyst then.

The catalyst that makes as stated above carries out activity rating in the isotherm formula fixed bed, process is summarized as follows:

Deionized water and ethylbenzene are imported preheating mixer through measuring pump respectively, and preheating enters reactor after being mixed into gaseous state, and reactor adopts the heating wire heating, makes it to reach predetermined temperature.Reactor inside diameter is 1 " stainless steel tube, it is interior that to load 100 milliliters, particle diameter be 3 millimeters catalyst.Analyzing it with gas chromatograph by the reactant of reactor outflow behind water condensation forms.

Conversion of ethylbenzene, selectivity of styrene and styrene list are received as follows and are calculated:

The styrene list is received %=conversion of ethylbenzene % * selectivity of styrene %

The present invention is by adopting the oxide that adds an amount of niobium in iron-potassium-cerium-molybdenum-magnesium-calcium system, the potassium oxide weight content is below 11% in the control catalyst, be surprised to find that made low potassium catalyst have selectivity of styrene up to 95.5%, catalytic activity is up to 78.2% outstanding advantage, obtained better technical effect.

The invention will be further elaborated below by embodiment.

The specific embodiment

[embodiment 1]

With 300.0 gram iron oxide reds, 160.0 gram iron oxide yellow, 50.1 gram potash, 70.0 gram cerous nitrate, 9.2 gram ammonium molybdate, 9.0 gram magnesia, 6.0 gram calcium oxide, 0.5 gram niobium oxide, 3.0 gram cupric oxide, 2.0 gram nickel oxide and 16.0 gram cement, 15.0 the gram carboxymethyl cellulose stirred in kneader 1 hour, add deionized water, mix and stir half an hour again, take out extrusion, be extruded into 3 millimeters of diameters, the particle that length is 8～10 millimeters, put into baking oven, 80 ℃ were dried by the fire 2 hours, 120 ℃ were dried by the fire 2 hours, place muffle furnace then, obtained finished catalyst in 4 hours in 850 ℃ of roastings.

With 100 milliliters of catalyst reactor of packing into, normal pressure, liquid air speed 1.0 hours ^-1, 620 ℃, water are than carrying out activity rating under (weight) 2.0 conditions, evaluation result is listed in table 1.

[embodiment 2]

Method by embodiment 1 prepares catalyst, and different is with 260.0 gram iron oxide reds, 130.0 gram iron oxide yellows, 55.0 gram potash, 103.2 gram cerium oxalates, 5.5 gram ammonium molybdates, 6.5 gram magnesia, 14.6 gram calcium carbonate, 3.6 gram niobium oxide, 6.1 gram zinc oxide, 2.0 gram boron oxides and 18.0 gram cement, 16.0 gram carboxymethyl celluloses.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[embodiment 3]

Method by embodiment 1 prepares catalyst, and different is with 240.0 gram iron oxide reds, 120.0 gram iron oxide yellows, 60.0 gram potash, 100.0 gram cerous nitrates, 10.0 gram ammonium molybdates, 8.8 gram magnesia, 12.0 gram calcium oxide, 5.8 gram niobium oxide, 8.0 gram manganese oxide, 2.0 gram aluminium oxide and 24.0 gram cement, 16.0 gram carboxymethyl celluloses.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[embodiment 4]

Method by embodiment 1 prepares catalyst, and different is with 240.0 gram iron oxide reds, 120.0 gram iron oxide yellows, 65.0 gram potash, 90.0 gram cerium oxalates, 8.2 gram ammonium molybdates, 10.0 gram magnesia, 7.5 gram calcium carbonate, 8.7 gram niobium oxide, 8.0 gram cupric oxide, 4.2 gram aluminium oxide and 20.0 gram cement, 18.0 gram carboxymethyl celluloses.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[embodiment 5]

Method by embodiment 1 prepares catalyst, and different is with 270.0 gram iron oxide reds, 140.0 gram iron oxide yellows, 76.0 gram potash, 70.0 gram cerium oxalates, 8.2 gram ammonium molybdates, 5.1 gram magnesia, 5.7 gram calcium carbonate, 15.0 gram niobium oxide, 3.6 gram manganese oxide, 1.6 gram boron oxides and 20.0 gram cement, 15.0 gram carboxymethyl celluloses.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

The weight percent of gained catalyst is composed as follows:

Form	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4	Embodiment 5
						Fe 2O 3 K 2O CeO 2 MoO 3 MgO CaO Nb 2O 5 CuO Ni 2O 3 ZnO B 2O 3 MnO 2 Al 2O 3	80.05 6.45 5.17 1.42 1.70 1.14 0.09 0.57 0.38 - - - -	72.47 7.57 10.09 0.91 1.31 1.66 0.73 - - 1.23 0.40 - -	69.03 8.52 8.13 1.70 1.83 2.50 1.21 - - - - 1.67 0.42	68.87 9.20 9.08 1.39 2.08 0.87 1.81 1.66 - - - - 0.87	72.79 10.00 6.56 1.29 0.98 0.62 2.90 - - - 0.31 0.70 -

[comparative example 1]

Except that not adding the niobium oxide, all the other are all identical with embodiment 1.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[comparative example 2]

Except that not adding the niobium oxide, all the other are all identical with embodiment 2.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[comparative example 3]

Except that not adding the niobium oxide, all the other are all identical with embodiment 3.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[comparative example 4]

Except that not adding the niobium oxide, all the other are all identical with embodiment 5.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

[comparative example 5]

Except that adding 30.0 gram niobium oxide, all the other are all identical with embodiment 5.

Appreciation condition by embodiment 1 carries out activity rating, and evaluation result is listed in table 1.

The weight percent of gained catalyst is composed as follows:

Form	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
						Fe 2O 3 K 2O CeO 2 MoO 3 MgO CaO Nb 2O 5 CuO Ni 2O 3 ZnO B 2O 3 MnO 2 Al 2O 3	80.11 6.47 5.18 1.42 1.71 1.14 - 0.57 0.38 - - - -	73.00 7.62 10.16 0.91 1.32 1.67 - - - 1.24 0.41 - -	69.87 8.62 8.23 1.72 1.86 2.53 - - - - - 1.69 0.42	74.96 10.29 6.75 1.33 1.01 0.64 - - - - 0.32 0.72 -	70.74 9.71 6.37 1.25 0.96 0.60 5.63 - - - 0.30 0.68 -

The contrast of table 1 catalyst performance

Catalyst	Conversion ratio %	Selectivity %	Single % that receives
				Embodiment 1 embodiment 2 embodiment 3 embodiment 4 embodiment 5 comparative examples 1 comparative example 2 comparative examples 3 comparative examples 4 comparative examples 5	77.6 77.9 78.2 78.1 77.5 77.5 77.4 77.2 77.3 77.0	94.8 95.2 95.5 95.3 94.7 94.2 93.8 93.6 94.1 94.3	73.56 74.16 74.68 74.43 73.39 73.01 72.60 72.26 72.74 72.61

Above embodiment explanation adds an amount of niobium oxide component in iron-potassium-cerium-molybdenum-magnesium-calcium system, not only significantly improved low potassium selection of catalysts, also helps the raising catalytic activity, is a kind of good high-selectivity catalyst.

Claims (2)

1, a kind ofly be used to prepare cinnamic dehydrogenation, comprise following component by weight percentage:

(a) 60～88% Fe ₂O ₃

(b) 6～11% K ₂O;

(c) 4～11% CeO ₂

(d) 0.5～5% MoO ₃

(e) 0.5～5% MgO;

(f) 0.05～5% CaO;

(g) 0.05～5% Nb ₂O ₅

(h) 0.001～8% at least a oxide that is selected from Cu, Al, B, Zn, Mn, W, Ni, Sn, Pb, Bi, Ge.

2, be used to prepare cinnamic dehydrogenation according to claim 1 is described, it is characterized in that by weight percentage Nb ₂O ₅Consumption be 0.2～2%.